Hi . Have you asked your doctor which is best? We're not medical experts, but I would guess that the first regime would be healthiest, if you are comfortable with it, because you are maintaining or increasing muscle mass and balance while also improving your cardiovascular health. But you only need to lift weights once every two or three days to reap the muscle-building or muscle-maintanance benefits. Slow treadmill walking in between would give your body a break while manitaining the cardiovascular effeciency. Whatever you decide, let your body guide you. If it feels too hard or makes you uncomfortable, it's probably best to stop or slow down. Maybe you could ask your doctor about signs and symptoms to look for.
I hope this helps.
Lori (Team Member)